1. Field of the Invention
The invention relates to a flexible line element, particularly for exhaust pipes of internal combustion engines for motor vehicles, with a screw thread-like or annularly corrugated bellows provided with cylindrical connection ends, and a metal netting or braid arranged coaxially to and in contact with the bellows.
2. Description of the Prior Art
Such line elements are introduced in the form of adaptors into the exhaust pipe, which is normally installed in fixed manner on the vehicle floor, optionally accompanied by the interposing of flexible support parts, in order to absorb movements and vibrations and prevent the transfer thereof to adjacent components, such as occur through the elastically mounted engine, vehicle faults, temperature-caused length changes, etc. If there is a lack of bellows damping, in the resonant range of the free bellows increased movements occur thereto, leading to a reduction in the service life and interact with other components for producing noise.
EP 681 096 A1 describes a flexible line element, in which the bellows is surrounded by a knitted fabric tube fixed at both bellows ends. The knitted fabric tube supports the bellows axially in both directions, because the meshes can be moved in both the tension and pressure directions and there are limits to the movement thereof in both directions. However, it is disadvantageous that the line element is relatively unprotected to the outside, because it is possible for impurities or particles, e.g. gravel or loose stones, to be fixed in the mesh gaps, so that the mobility of the knitted fabric is impaired in such a way that the axial mobility of the line element overall is reduced and consequently so is its decoupling action. Moreover, the knitted fabric is not only flat, but also has a finite, compressible height, so that the knitted fabric can also be compressed, accompanied by a lose of its action.
German utility model 296 09 293.2 discloses a flexible line element with a knitted fabric tube directly surrounding the bellows and which additionally has a braided tube completely externally surrounding the knitted fabric hose and positioned coaxially to the line element. The braided tube is fixed to the connection ends of the line element, so that the knitted fabric hose surrounding the bellows is protected against pollution and dirt applied from the outside. This construction is relatively expensive, because the line element is formed from three different types of tubes and the damping function and protective function are fulfilled by different components.